1. Field of the Invention
The present invention relates to a modified chain aliphatic polyamine and a composition containing the same. The present invention also relates to a curing agent for epoxy resin comprising said modified chain aliphatic polyamine, an epoxy resin composition comprising said curing agent for epoxy resin, and an epoxy resin cured product obtained by curing said epoxy resin composition. In the present invention, the term “chain aliphatic” includes an acyclic aliphatic compound.
The modified chain aliphatic polyamine is applicable to a curing agent for epoxy resin and a raw material thereof to be utilized in an extremely wide field including application to a coating material, a material for electricity and electronics, a civil engineering and construction material, an adhesive, and a composite material; and is applicable to a chain extender and a raw material thereof of a polyurethane resin to be utilized in a very wide field including clothes, sports equipments, home appliances, electronics, medical apparatuses, motor cars, transporting apparatuses, civil engineering and construction materials and industrial materials as a foam, an elastomer, a coating, an adhesive, a binder, fibers, a leather, a flooring material, a water proof material, an athletic material, a sealant, a coking, a medical material and a fiber treating agent. Furthermore, it can be utilized widely in various field such as a paper reinforcing agent, chemicals for rubber, boiler compounds, a slag inhibitor, a surfactant, an emulsifier, a dye, a pigment, a dyeing assistant, an oil solution for fiber, cosmetics, a crease-proofing agent, a chelating agent, a ore floatation agent, a detergent, a thixotropic agent, a pH adjuster, a pesticide, a herbicide, a stabilizer for agricultural chemicals, feed additives, catalysts, a polymerization accelerator, a polymerization inhibitor, a stabilizer, an ion-exchange resin, a gas absorbent, an antioxidant, a corrosion inhibitor, an antirust, a sterilizer, an antibacterial agent, an antifreeze liquid, a lubrication oil, a lubricant, an intermediate of pharmaceuticals, polyamide, a solvent and photographic chemicals.
2. Related Art
It has widely been known that various polyamines are used as a curing agent for epoxy resin and a raw material for curing agent thereof or a chain extender for polyurethane resin and a raw material for chain extender thereof.
However, these polyamines are scarcely used as it is as a curing agent for epoxy resin. In most cases, they are used after various modifications suitable for their own characteristics caused by the reactivity of their amino groups, namely active hydrogen atoms that each polyamine has, depending on the intended purpose such as improving in safety and hygiene, improving in workability and providing of adequate property of cured products suitable for their own application.
For example, Japanese Patent Kokai (Laid-open) No. 2002-161076 describes that a curing agent for epoxy resin obtained by modifying metaxylylenediamine and the like provides an epoxy resin composition having a long pot life.
Representative methods for a modification of polyamines include 1) a modification by Mannich reaction with a phenol compound and an aldehyde compound, 2) a modification by reaction with an epoxy compound, 3) a modification by reaction with a compound having a carboxyl group, 4) a modification by Michael reaction with an acryl compound and 5) combinations of any of 1) to 4).
In general, the molar number of modification of polyamine is selected from the range wherein the obtainable modified polyamine has at least one active hydrogen atom derived from the amino groups in the polyamine before modification.
When the molar number of modification is relatively low, the obtainable modified polyamine has a low viscosity. However, the amount of unreacted polyamine becomes large, which causes such defects that the obtainable modified polyamine may have high toxicity and skin irritativeness may remain. Moreover, the epoxy resin composition using the modified polyamine as a curing agent for epoxy resin may have such defects that the appearance of a coating film tends to be inferior by the phenomena of whitening or tackiness because such epoxy resin composition easily produces carbamate or carbonate by absorbing carbon dioxide or water vapor in the atmosphere.
On the other hand, when the molar number of modification is relatively high, the content of unreacted polyamine in the obtainable modified polyamine is small. However, the viscosity of the modified polyamine becomes high, which brings about the requirement of lowering the viscosity by adding solvents or diluents in order to improve workability.
It is desired not to use solvents because of environmental problems and to limit the amount of diluents added in order to avoid the deterioration of the properties of cured products.